The painting of workpieces by spraying with electrostatically charged paint particles is well known in the art. The technique is widely used due to its many advantages. For example, paint waste is drastically reduced, because the charged paint particles are attracted to the workpiece. This electrostatic attraction also insures a more uniformly coated workpiece and also assists in coating hard-to-reach portions of the workpiece.
In spite of its advantages, the prior art apparatus is not without its drawbacks. One such drawback arises from the fact that the paint is atomized by being expelled at relatively high pressure through small orifices. These small orifices, while serving to atomize the paint, also restrict the throughput (pounds of paint per minute) of the apparatus.
Another disadvantage arises from the high potential gradient that exists between the electrode in the nozzle of prior paint spraying apparatus and the workpiece. If the nozzle of a prior paint sprayer approaches the workpiece too closely, sparking between the grounded workpiece and the nozzle may result, which creates a fire hazard in the paint-laden atmosphere.
Accordingly, primary objects of this invention are to increase the paint throughput of such paint spraying apparatus and to substantially eliminate the dangers of sparking between the paint sprayer and the workpiece. Other objects, features, and advantages will become understood from the following description in conjunction with the drawings and appended claims.